Gas analyzers, such as for example those that employ tunable diode laser spectroscopy, typically require mounting of a laser source on a heat sink or a thermo electric cooler (TEC) to achieve and maintain the required lasing frequency for a chosen trace gas analysis. A thermistor and an electronic feedback control loop are typically used to stabilize laser temperature to the required accuracy levels. However, laser temperature stability can be influenced by ambient temperature conditions, especially by changing ambient temperature conditions. Changing temperature conditions can in some instances exceed the ability of the control circuit to maintain laser temperature and frequency at the required levels. If this cannot be achieved, the laser may shift away from its pre-set frequency, thereby generating unacceptable measurement errors.
Currently available TDL-based gas analyzers typically employ an insulated enclosure coupled to a heater to maintain the enclosure temperature at a relatively constant value that is elevated relative to typically encountered ambient conditions. These heated enclosures can require substantial energy consumption. In addition, if the gas analyzer is installed in a location where it might be exposed to hazardous and/or flammable compounds, additional costs can be added by the requirement of using a hazardous location approved heater and thermostat. At rural installations, electricity supplies can be limited, and provision of 200 or more watts to run a heater enclosure device can be problematic. Use of TDL-based gas analyzers with natural gas pipelines is increasing. Such pipelines typically run long distances over which easy access to AC power is limited or non-existent. Solar panels or thermo electric generators can be used. However, it can be difficult to supply more than 50 W power at acceptable cost levels with these generation sources.